Development and application of a novel electrochemical immunosensor for tetracycline screening in honey using a fully...

Tetracycline (TC) is a veterinary drug, wildly prescribed for prophylactic and therapeutic purposes. Consequently, its remaining residues in food products have to be regularized. We report in this paper about the development of a novel immunosensor based on an integrated bio micro-electromechanical system (Bio-MEMS) containing eight gold microelectrodes (µWEs), an integrated silver and platinum reference and counter electrodes, respectively. TC immobilization on the µWEs surface was conducted using three methods. The first through functionalization with 4-aminophenylacetic acid (CMA), the second by functionalization with CMA followed by preconcentration of a new structure of magnetic nanoparticles (MNPs) coated with poly (pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH/MNPs) cross-linked with Ab-TC, and the last one directly through the functionalization with Py/Py-COOH/MNPs. The analyte was quantified by competitive detection with TC immobilized on the µWEs surface toward specific polyclonal antibody (Ab-TC), using a mixture of a fixed concentration of Ab-TC and decreasing levels of TC one from 0.1 pg mL^-1 to 1000 pg mL^-1. Microcontact printing, followed by fluorescence microscopy characterization were performed during the functionalization of the immunosensor surface to certify that the corresponding immune detection process is taking place. This immunosensor was found to be highly sensitive with a limit of detection of 1.2 pg mL^-1 and specific in the presence of interferents. The standard addition method was exploited to detect TC in honey samples. The present immunosensor platform is up-and-coming for TC detection which can dramatically decrease the time of analysis providing a new pathway for advanced immunoassays development in industrial food control.